Dimensional Check of the APU Vibration Isolators (131-9(A))

TASK 49-12-00-220-002-A
Dimensional Check of the APU Vibration Isolators (131-9(A))

WARNING: DO NOT TOUCH THE APU UNTIL IT IS SUFFICIENTLY COOL TO PREVENT BURNS WHEN YOU DO THE MAINTENANCE TASK(S).

FIN: 4055KM ** ON A/C NOT FOR ALL
FIN: 4065KM ** ON A/C NOT FOR ALL
FIN: 4075KM ** ON A/C NOT FOR ALL

1. Reason for the Job
Self Explanatory
2. Job Set-up Information
A. Fixtures, Tools, Test and Support Equipment

REFERENCE	QTY	DESIGNATION
No specific	1	ACCESS PLATFORM 4M (13 FT)-ADJUSTABLE
No specific	AR	GAGE - CALIPER
No specific	AR	SAFETY CLIP - CIRCUIT BREAKER

B. Work Zones and Access Panels

ZONE/ACCESS	ZONE DESCRIPTION
315AL, 316AR

C. Referenced Information

REFERENCE	DESIGNATION
TASK 24-42-00-861-001-A	Energize the Ground Service Network from the External Power
TASK 24-42-00-862-001-A	De-energize the Ground Service Network Supplied from the External Power
TASK 29-00-00-864-001-A	Put the Related Hydraulic System in the Depressurized Configuration before Maintenance Action
TASK 49-12-51-000-003-A	Removal of the FWD LH Tie-Rods and Vibration Isolator (131-9(A))
TASK 49-12-51-400-003-A	Installation of the FWD LH Tie -Rods and Vibration Isolator (131-9(A))
TASK 49-12-52-000-003-A	Removal of the FWD RH Tie-Rods and Vibration Isolator (131-9(A))
TASK 49-12-52-400-003-A	Installation of the FWD RH Tie-Rods and Vibration Isolator (131-9(A))
TASK 49-12-53-000-003-A	Removal of the AFT Tie-Rods and Vibration Isolator (131-9(A))
TASK 49-12-53-400-003-A	Installation of the AFT Tie-Rods and Vibration Isolator (131-9(A))
TASK 49-12-54-000-003-A	Removal of the APU Mount Brackets (131-9(A))
TASK 49-12-54-400-003-A	Installation of the APU Mount Brackets (131-9(A))
TASK 52-41-00-010-001-A	Open the APU Doors for Access
TASK 52-41-00-410-001-A	Close the APU Doors after Access
APU Suspension

3. Job Set-up
Subtask 49-12-00-860-070-A ** ON A/C NOT FOR ALL

A. Aircraft Maintenance Configuration
(1) Energize the ground service network
(Ref. AMM TASK 24-42-00-861-001).
(2) On the panel 25VU make sure that the APU MASTER SW p/bsw is OFF.
(3) Put the warning notices on panel 25VU to tell persons not to start the APU.
(4) Make sure that the hydraulic systems are depressurized
(Ref. AMM TASK 29-00-00-864-001).

Subtask 49-12-00-865-072-A ** ON A/C NOT FOR ALL

B. Open, safety and tag this(these) circuit breaker(s):

PANEL	DESIGNATION	FIN	LOCATION
** ON A/C NOT FOR ALL
121VU	APU/APU/CTL	2KD	L42
121VU	APU/ECB/SPLY	1KD	L41

Subtask 49-12-00-010-061-A ** ON A/C NOT FOR ALL

C. Get Access
(1) Put the ACCESS PLATFORM 4M (13 FT)-ADJUSTABLE in position below the APU access doors 315AL and 316AR.
(2) Open the APU access doors 315AL 316AR and safety them in the open position (Ref. AMM TASK 52-41-00-010-001).
(3) Set the LIGHT control SW 11LJ to the ON position.

4. Procedure
Subtask 49-12-00-220-056-A ** ON A/C NOT FOR ALL

A. Dimensional check of the APU vibration isolators
(1) Measure the distance between the lower surface of the vibration isolator and the upper surface of the APU mount brackets with a GAGE - CALIPER.
(2) Make sure that the measured distances are not more than the permitted dimensions DIM A and DIM B.

DIM A is max 9.5 mm (0.3740 in.).
DIM B is max 18.0 mm (0.7087 in.).

(a) If the measured distance on any or all of the vibration isolator(s) is more than the permitted DIM A and DIM B, replace all vibration isolators as follows:

FWD LH tie-rods and vibration isolators (Ref. AMM TASK 49-12-51-000-003) and (Ref. AMM TASK 49-12-51-400-003).
FWD RH tie-rods and vibration isolators (Ref. AMM TASK 49-12-52-000-003) and (Ref. AMM TASK 49-12-52-400-003).
AFT tie-rods and vibration isolators (Ref. AMM TASK 49-12-53-000-003) and (Ref. AMM TASK 49-12-53-400-003).

(3) Make sure that the components are in correct condition.
(a) If a component is not in correct condition, replace it:

FWD LH tie-rods and vibration isolators (Ref. AMM TASK 49-12-51-000-003) and (Ref. AMM TASK 49-12-51-400-003).
FWD RH tie-rods and vibration isolators (Ref. AMM TASK 49-12-52-000-003) and (Ref. AMM TASK 49-12-52-400-003).
AFT tie-rods and vibration isolators (Ref. AMM TASK 49-12-53-000-003) and (Ref. AMM TASK 49-12-53-400-003).
APU mount brackets (Ref. AMM TASK 49-12-54-000-003) and (Ref. AMM TASK 49-12-54-400-003).

5. Close-up
Subtask 49-12-00-410-061-A ** ON A/C NOT FOR ALL

A. Close Access
(1) Make sure that the work area is clean and clear of tools and other items.
(2) Set the LIGHT SW 11LJ to the OFF position.
(3) Close the APU access doors 316AR 315AL (Ref. AMM TASK 52-41-00-410-001) .
(4) Remove the ground support and maintenance equipment, the special and standard tools and all other items.
(5) Remove the access platform(s).

Subtask 49-12-00-865-073-A ** ON A/C NOT FOR ALL

B. Remove the safety clip(s) and the tag(s) and close this(these) circuit breaker(s):

PANEL	DESIGNATION	FIN	LOCATION
** ON A/C NOT FOR ALL
121VU	APU/APU/CTL	2KD	L42
121VU	APU/ECB/SPLY	1KD	L41

Subtask 49-12-00-860-071-A ** ON A/C NOT FOR ALL

C. Aircraft Maintenance Configuration
(1) Put the related hydraulic system in the pressurized configuration (Ref. AMM TASK 29-00-00-864-001).
(2) De-energize the ground service network
(Ref. AMM TASK 24-42-00-862-001).
(3) Remove the WARNING NOTICE(S).

[Rev.10 from 2021] 2026.04.01 01:27:00 UTC